The present invention relates to an apparatus for preparing dialysate solutions wherein a powder including a granule is dissolved by a dissolving solution.
Hitherto, preparation of dialysate solutions has been performed in a tank system. In the tank system, prescribed quantities of a dissolving solution and powder are introduced into a solution tank, and then stirred by a stirring pump or a stirring blade and mixed to form a dialysate solution. The prepared dialysate solution is transferred to a point of use by a delivery pump. At this time, the level of the solution in the solution tank is lowered, and a negative pressure is generated in the solution tank and thus outside air is introduced into the solution tank. The introduction of air occurs in the tank system because the solution tank is generally opened to the air to prevent breakage of the solution tank itself by a negative pressure generated therein. Therefore, in many cases, an air filter is provided at a portion opened to the air to prevent bacteria or the like contained in the outside air from entering. The use of an air filter results in problems and a high cost for replacing the air filter on a regular basis. As a matter of fact, there are cases where a filter that prevents only dust is used, or even no filter is used considering the above problems and cost, but this procedure is not preferable. In addition, in a tank system, when an attempt is made to prepare a large quantity of solution at a time, a large solution tank is necessary, thereby disadvantageously increasing the size of the apparatus itself. Moreover, since many stirring pumps and delivery pumps are necessary, the operating noise may disadvantageously be too loud. When an abnormal concentration is found after preparation, adjustment of the concentration of the dialysate solution cannot be made in the conventional tank system, whereby the dialysate solution has to be discarded. This is economically disadvantageous.
With a view to the circumstances described above, an object of the present invention is to provide a cost effective apparatus for preparing dialysate solutions in which replacement of an air filter for preventing bacteria or the like from entering into the solution tank is essentially unnecessary, and miniaturization of the entire system and lowering of operation noise are possible. Also, an object is to provide an apparatus for preparing dialysate solutions in which a concentration of a dialysate solution can be finely adjusted.
After dedicated studies, the inventor found that the above-described objects can be achieved by utilizing a chamber which is divided into three compartments, a first compartment, a second compartment and a third compartment, by movable partitions so that a dialysate solution can be prepared within a circuit containing the first compartment and the third compartment of the chamber while substantially preventing outside air from entering therein, and that the capacities of the first and the third compartments can be changed by changing the capacity of the second compartment, and reached the present invention. Stated differently, the present invention is an apparatus for preparing a dialysate solution comprising a chamber which is divided into three compartments, i.e., a first compartment, a second compartment and a third compartment, by movable partitions; a dissolving solution supply line for supplying a dissolving solution to the first compartment of the chamber; a dialysate solution preparing line connecting the first compartment and the third compartment of the chamber; a solution tank connected to the first compartment and a transporting pump connected to the third compartment and which are provided in the dialysate solution preparing line; powder supply means provided above the solution tank; a dialysate solution transporting line for transporting the dialysate solution prepared and filled in the third compartment to the point of use; a circulating line connecting the dialysate solution transporting line with the dialysate solution preparing line between the solution tank and the transporting pump, and a by-pass line for bypassing the solution tank and connecting the first compartment with the third compartment, in which the quantity of dissolving solution to be supplied to the first compartment and the quantity of dialysate solution to be transported to the third compartment can be adjusted by charging and a liquid to or discharging a liquid from the second compartment of the chamber.
The solution tank may be provided with a liquid level detecting sensor. It is preferable that a concentration meter is provided in the circuit comprising the third compartment of the chamber, the dialysate solution transporting line, the circulating line, and the dialysate solution preparing line. The dissolving solution supply line may be provided with a second dissolving solution supply line.
The apparatus for preparing a dialysate solution of the present invention is preferably constructed in such a manner that a second chamber which is divided into three compartments by movable partitions is connected to the dissolving solution supply line, the dialysate solution preparing line, and the dialysate solution transporting line so that the preparation of the dialysate solution can continuously be performed.